• 제목/요약/키워드: limitation

검색결과 8,420건 처리시간 0.029초

Isolation and Characterization of a Methylotroph Producing 3-hydroxybutyrate-3-hydroxyvalerate Copolymer

  • JUNG HOE KIM;KIM, PIL;SEON WON KIM;GYUN MIN LEE;HYUN SOO LEE
    • Journal of Microbiology and Biotechnology
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    • 제5권3호
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    • pp.167-171
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    • 1995
  • A bacterial strain C-02 using methanol as a carbon source was isolated from Gumi Industrial Estate and selected based on its rapid growth and capability of poly-$\beta$-hydroxybutyrate accumulation. Characteristics of strain C-02 showed that it belongs to the Methylococcaceae family, Type II subgroup. Strain C-02 could incorporate valerate into the PHB chain to form 3-hydroxybutyrate and 3-hydroxyvalerate (P(3HB-co-3HV)). Among various nutrient limitation tests, the nitrogen limitation test resulted in the highest content of P(3HB-co-3HV) per dry cell weight, 50$%$. Under the nitrogen limited condition, the average molecular weight of P(3HB-co-3HV) obtained was determined to be approximately $2.8\times 10^5$ daltons.

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Development of radiotracer for polo-box domain of polo-like kinase 1

  • Ryu, Eun Kyoung
    • 대한방사성의약품학회지
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    • 제5권2호
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    • pp.152-157
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    • 2019
  • Polo-like kinase 1 (Plk1) is crucial regulator of cell cycle progression during mitosis. It is known to highly overexpress in many different tumor types, and has been implicated as a potential antimitotic cancer target. The phosphopeptide, Pro-Leu-His-Ser-p-Thr (PLHSpT), was shown a high level of affinity and specificity for the polo-box domain (PBD) of Plk1. However, the peptide has the limitation of cell permeability. We designed the derivatives to enhance the limitation of PLHSpT using drug delivery system. In addition, we synthesized and evaluated its radiotracer for tumor diagnosis. This review discusses the derivative and radiotracer that are suitable for tumor treatment and diagnosis for PBD of Plk1.

표면전자도핑 기법을 활용한 각분해능 광전자분광 연구 (Angle resolved photoemission spectroscopy with surface-electron-doping)

  • 김용관
    • 진공이야기
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    • 제3권4호
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    • pp.19-23
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    • 2016
  • Angle resolved photoemission spectroscopy (ARPES) is a powerful technique which can directly visualize the electronic structure of solid in detail including many-body interaction information. However, ARPES has a certain limitation in applying control parameters such as doping or pressure, which helps to dig out the clue to understand the desired phenomena or the target system. During ARPES experiment, the control parameter is the temperature only. Other parameters especially electric- and magnetic- field cannot be applied. Recently introduced surface-electron doping technique highlights new avenue to overcome such limitation. In this article, starting from introducing basic concepts of ARPES and its current status, the power of new technique will be demonstrated when it is combined to ARPES by introducing recent results on iron based superconductors.

SRG의 안정발전제동을 위한 기준전류 제한방식에 관한 연구 (Reference Current Limit Control for Stable Generative Breaking of SRG)

  • 김태형;박성준;안진우
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.69-71
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    • 2003
  • Switched reluctance machine has much attention because of high efficiency, high power and DC series torque characteristics with a traction drive. But the motor has to have a regenerative mode when it is adopted in an electric vehicle. A current divergence during the regeneration makes difficulties in the control of SRM. This paper proposes a reference current limitation strategy for a stable regeneration based on simulations and experimental tests. The motor is operated with conventional current limit and switching angle control method in motoring mode. Simulations and experiments are executed to verify proposed method.

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일 도시지역 취약노인의 우울 유병률과 영향 요인 (Prevalence and Its Influencing Factors on Depression among Elderly Vulnerable People in Urban Community)

  • 김혜령
    • 보건의료산업학회지
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    • 제7권3호
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    • pp.275-286
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    • 2013
  • To identify the prevalence and its influencing factors on depression among elderly vulnerable people in one urban community. This study used data from 381 of elderly vulnerable people in the community. The prevalence of depression was found to be 51.97%. Multivariate logistic regression analysis shows that depression was more prevalent as people in female gender; people with lower self-esteem compared to those with higher self-esteem; in elderly who perceived lower social support compared to those who perceived higher social support; and in the older adults with limitation in instrumental activity of daily living. The finding of a significant association between gender difference; self-esteem; perceived social support, and limitation in instrumental activity of daily living and occurrence of depression expected to promote the screening strategy for elderly at risk of depression in Korean community.

이동 컴퓨팅 환경에서 방송기반의 낙관적 캐쉬 프로토콜들에 대한 분석 (Analysis of Optimistic Cache Protocols based on broadcasting for Mobile Computing Environments)

  • 조성호
    • 인터넷정보학회논문지
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    • 제6권5호
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    • pp.177-185
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    • 2005
  • 이동 컴퓨팅 환경에서 캐싱은 통신대역폭의 한계, 자원의 제약과 잦은 접속단절의 영향을 줄일 수 있는 중요한 기술이다. 이동 컴퓨팅의 이러한 제약과 접속단절을 완화하기 위하여 방송 기반의 새로운 캐싱 기법이 소개되었다. 이 논문에서는 새로운 방송기반 캐쉬 프로토콜을 제안하고 다중버전 방식 및 확인보고 방식과 같이 잘 알려진 기법과 비교한다. 모의실험을 통하여 충돌을 검출하고 해결하는 여러 접근방법들의 특징을 보여준다. 또한, 제안하는 기법이 다른 방식에 비하여 공간 및 계산 부하가 적다는 것을 보인다.

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국제상거래법상 Force Majeure와 Hardship에 관한 고찰 (A Study on Force Majeure and Hardship in the International Sales Laws)

  • 오현석
    • 무역상무연구
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    • 제69권
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    • pp.179-199
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    • 2016
  • There is legal relation between both parties after contract formation. The parties are liable for performing each duties but a party is not liable for a failure to perform the duties if party proves that the failure was due to the force majeure. The forec majeure has different concepts and legal principles such as change circumstance, hardship, frustration, impediment and so on. Therefore, it need to analyze a historical background and their presence in various domestic legal systems. Although the CISG describes Art. 79 impediment instead of using the force majeure, the impediment has several interpretative limitation. The CISG pursue to harmonize divergent legal concepts and principles from various national laws and legal systems but the harmonization of legal systems make the impediment more confused. The article goes on to analyzes about limitation of the impediment and reviews to examine the force majeure and hardship in PICC. Thus both parties of international contract insert hardship clause in order to prevent the problem of judgment in a court or a court of arbitration under impediment of CISG.

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나노 구조물을 이용한 전자선 차폐 가능성과 한계 조사 (Possibility & Limitation of 1D Nano Scale Electron Shielder)

  • 안성준;이범수;김종일
    • 방사성폐기물학회지
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    • 제5권2호
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    • pp.109-112
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    • 2007
  • 나노 규모의 1차원 양자 구조물을 이용한 전자선 차폐 가능성에 관한 이론적 배경과 한계를 정리한다. 나노 구조물을 이용한 전자선 차폐는 차폐재의 경량화와 소형화에 크게 기여할 것으로 예상되나, 실용화를 위해서는 아직 연구되어야 할 분야가 많다. 임의의 1차원 포텐셜 장벽을 대상으로 양자투과계수 계산을 실행하여, 나노 구조물의 전자선 차폐와 관련된 문제점들을 살펴본다.

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공학적 접근을 통한 해체비용 산정 프레임워크에 대한 고찰 (A Study on Decommission Cost Estimation Framework with Engineering Approach)

  • 이선기
    • 시스템엔지니어링학술지
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    • 제8권2호
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    • pp.57-67
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    • 2012
  • It is the sensitivity and confidentiality of nuclear power plant decommissioning cost that prevent detailed cost information to be released to the public, which causes some limitation to analyze and reuse the costs. This limitation to access cost information means that the lessons learned from preceding cost estimating may not systematically feed back into following cost estimates. As an alternative, decommissioning cost estimation framework is indispensable to reflecting available experience and knowledge for decommission costs. This study provides the cost estimation framework including data flow and structuralization based on engineering and bottom up approach to enhance decommissioning cost estimation.

DC링크 전류센서를 이용한 삼상전류 측정 방식에서 최소 스위칭 시간의 단축 (Reduction of Minimum Switching Duration in the Measurement of Three Phase Current with DC-Link Current Sensor)

  • 김경서
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제52권12호
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    • pp.649-654
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    • 2003
  • The simplest method for measuring output currents of the three phase inverters is to measure them with three current sensors such as hall sensors. This method requires at least two current sensors, and these types of sensors are somewhat expensive. More economical method is measuring DC link current with a simple shunt resistor, then, reconstructing output current using the DC link current value and the switching status. However, in low speed region, the measurement becomes difficult and even impossible due to the requirement of minimum switching duration for A/D conversion. These problems can be overcome by limitation of switching duration. Limitation of switching, however, causes voltage and current distortion. Owing to compensation, distortion can be effectively suppressed. However these increase acoustic noise due to increment of current ripple. In this paper, a current measurement method is proposed, which can reduce minimum switching duration resulting in reduction of acoustic noise. The validity of proposed method is confirmed through experiment.